The present invention relates to a press which comprises a plurality of injection plungers for simultaneously producing a plurality of moldings of plastics, particularly for producing packages of semiconductor circuits, and at least one injection mold, in the filling space of which a heated mold mass is pressed by each of the injection plungers through channels into associated cavities of the mold.
Presses comprising a plurality of injection plungers for producing packages of semiconductor integrated circuits are known. The semiconductor circuits, e.g. "chips", are mounted on a common metal strip which is placed in the injection mold. The mold is closed, and the semiconductor chips in the cavities, upon a molding process, are each enclosed in a separate plastic package. The plastics preferably used for this purpose are thermosetting plastics.
Such a press, in which an injection plunger is associated with a cavity, is disclosed in U.S. Pat. No. 4,347,211. For excess plastics material, each cavity communicates with a separate filling space or pot of the mold through a thin channel. If the plastics material to be molded was not exactly measured out, the excess plastics material is to flow off through the channels to the separate pots. However, these separate pots have an uncontrollable influence on the molding pressure; they make it impossible to keep any fairly exact limit of a molding pressure.